1. Field of the Invention
The invention relates to a control apparatus and control method for a Stirling engine and, more particularly, to a control apparatus and control method for starting a Stirling engine.
2. Description of Related Art
Technologies related to the starting of a Stirling engine are disclosed in, for example. Japanese Patent Application Publication No. 62-247160 (JP 62-247160 A) and Japanese Patent Application Publication No. 2004-301102 (JP 2004-301102 A). As technologies considered to be relevant to the invention, technologies related to the starting of an engine are disclosed in, for example, Japanese Patent Application Publication No. 2010-255548 (JP 2010-255548 A), Japanese Patent Application Publication No. 2004-360661 (JP 2004-360661 A), and Japanese Patent Application Publication No. 6-147068 (JP 6-147068 A).
If the maximum torque that can be produced by a Stirling engine is smaller than the torque needed to start the engine, it is impossible to start the Stirling engine by itself. Therefore, the starting of a Stirling engine is assisted by using a starter that drives an output shaft of the Stirling engine. However, if the driving of the starter is commenced without any special arrangement, a case can occur where large compression force acts on a piston, depending on the phase of the output shaft in some cases. Then, there arises a need to produce an engine-starting torque that is large enough to start engine even in such a case, by using the starter. This leads to an increase in the size and weight of the starter. In addition, increased cost may also result.